Hitherto, as the method of cleaning the heat exchanger incorporated in an indoor unit of a separate type air-conditioner, for example, after removing the filter and cover of the indoor unit, detergent is sprayed to the pipes and fins of the heat exchanger (evaporator) incorporated in the indoor unit, and the dirt sticking to the pipes and fins is cleaned and removed by the detergent.
At the time of, however, cleaning and removing the dirt sticking to the pipes and fins of heat exchanger in such manner as stated above, when the detergent is sprayed orthogonally to the cooling surface of the pipes and fins laid at the front side of the heat exchanger, part of the detergent is splashed back by the pipes and fins. When the detergent is blown by force to the pipes and fins, the outer surface of the indoor unit or the surrounding may be contaminated by the drift of the detergent, and it is difficult to clean and remove the stubborn dirt sticking to the pipes and fins.
Besides, since the pipes of the heat exchanger are arranged by staggering vertically or laterally, the spray of the detergent is disturbed by the pipes and fins arranged at the front side, and it is hard to blow the detergent directly to the pipes and fins arranged at the rear side. Besides, it was also hard to observe the state of contamination of the pipes and fins arranged at the rear side from the front side, and it took time and labor to clean the entire heat exchanger.